Characterization of heat transfer in R134a spray cooling.

A closed loop spray cooling system with R134-a as spray medium was used to investigate the performance of spray cooling characteristic. The heat transfer parameters such as heat flux, heat transfer coefficient and target surface temperature were studied under different volumetric flow rate and spray chamber pressure. The single-phase heat transfer region and the phase-change heat transfer region were analyzed at different heat fluxes. The results show that the heat flux, critical heat flux (CHF) and heat transfer coefficient directly relate with volumetric flow rate. The higher flow rate and spray chamber pressure could achieve higher CHF with better heat transfer performance. And the different relationship between heat transfer coefficient and surface temperature was obtained at different spray cooling period.